TCO-PEG3-amine | CAS 1800507-93-0

TCO-PEG3-amine is a strained trans-cyclooctene (TCO) click chemistry reagent bearing a short PEG3 spacer and a terminal primary amine for convenient conjugation and handle installation. As a bioorthogonal TCO partner commonly used in inverse electron-demand Diels–Alder (IEDDA) click reactions with tetrazines, it is widely adopted for labeling, surface functionalization, and modular assembly of molecular probes, imaging agents, and biomaterial constructs. The PEG spacer and amine functionality support aqueous compatibility and downstream coupling to targeting ligands, polymers, or biomolecule scaffolds, making it a practical building block in chemical biology workflows.

1. Tetrazine Probe Labeling

TCO-PEG3-amine is used as a TCO-bearing labeling handle for rapid, catalyst-free conjugation to tetrazine-functional probes, enabling efficient construction of fluorescent, luminescent, or affinity-based detection reagents. Researchers frequently incorporate the PEG3 spacer to improve solubility and reduce steric constraints during probe assembly, which is particularly valuable when preparing multicomponent imaging or assay reagents. The terminal amine further supports pre-functionalization strategies where the TCO moiety must be installed onto a larger platform before final tetrazine click coupling.

2. Antibody And Ligand Conjugation

TCO-PEG3-amine is applied in bioconjugation workflows that require installing a clickable TCO tag onto antibodies, antibody fragments, peptides, or other binding ligands prior to tetrazine-mediated assembly of reporter modules. The primary amine enables straightforward attachment to activated biomolecule surfaces or to intermediate linkers used in targeted reagent development, supporting modular build-and-attach strategies common in molecular imaging and diagnostic reagent research. PEG spacing helps maintain accessibility of the strained alkene for subsequent click reactions, which is important when generating conjugates with multiple functional domains.

3. Surface Functionalization For Biomaterials

TCO-PEG3-amine is suitable for functionalizing polymeric or hydrogel surfaces with TCO groups to create materials that can be patterned or decorated using tetrazine-containing reagents. In biomaterials science, the PEG3 spacer and amine functionality support robust incorporation into surface chemistries and scaffold attachment routes, allowing researchers to build reactive interfaces for immobilizing ligands, crosslinkers, or reporter molecules. This approach is frequently used to generate clickable material coatings for tool development in chemical biology and materials-based assay platforms.

4. Modular Linker For Imaging Reagents

TCO-PEG3-amine serves as a versatile linker building block for assembling modular imaging reagents where a TCO-functional component is prepared first and then coupled to a tetrazine-bearing reporter. The PEG3 chain provides a practical balance between flexibility and distance, helping reduce steric interference between the reporter and the reactive site during final assembly. The amine handle supports incorporation into larger conjugate architectures used by molecular imaging groups to rapidly interchange targeting or reporting components while maintaining a consistent clickable interface.